Insulation and sealing for basement

I want to replace the old exterior basement wall insulation (5 cm Styrofoam) with thicker insulation. The masonry is easily accessible for me, so I can definitely do it myself. I have already removed the old Styrofoam and the bitumen layer still looks very good. Nevertheless, I want to apply a new coating. Can I simply paint over it, or is it better to remove the old bitumen first? If so, what is the best way to do that?

A second coating should not be a problem, you can check the old bitumen coating for loose spots (which will most likely not be there). Simply scrape off any missing areas.

However, check (technical description, datasheet, processing instructions) whether the product you want to use for the renewed sealing is compatible with the old coating.